Effect of pre-sowing hardening treatments on germination, relative growth rate and yield of Pennisetum americanum (l) and s. Bicolor (Moench)
The effects of pre-sowing hardening treatment using 1 and 2 cycles of 1% calcium chloride, 50ppm ascorbic acid and 200ppm indole-3-butyric acid on embryo enlargement, relative growth rate and yields of Pennisetum americanum (cvs, ex Bornu, hairy compositae) and Sorghum bicolor (cvs, ksv11 and ksv12) were investigated. Seeds of the 2 cultivars of P. americanum and S. bicolor hardened with 2 cycles of water were employed as the controls. The 1 and 2 cycles of hardening treatments increased plumule and radicle lengths and relative growth rate of all the cultivars of P. americanum and S. bicolor with increases obtained for 2 cycles of hardening treatments being statistically significant. Yields of plants of 1 and 2 cycles ascorbic acid, calcium chloride and indole- 3-butyric acid treated seeds were significantly higher than those of the control plants. For all the cultivars of P. americanum and S. bicolor, 2 cycles of hardening treatments were generally better than 1 cycle of hardening treatments because they induced greater plumule and radicle growth, relative growth rate and yield. Out of the 4 hardening agents used in the study, indole-3-butyric acid stimulated the greatest plumule and radical lengths, relative growth and yield and was as such the best pre-sowing hardening agent. It was followed by ascorbic acid while water was the poorest.